A linear guide as an example of a motion guide device includes a track rail in which a plurality of ball rolling grooves are formed extending parallel to one another along a longitudinal direction and a movable block which is relatively movably mounted on the track rail via a plurality of balls. The movable block is constituted of a movable block body which has a loaded ball rolling groove forming a loaded ball rolling passage in cooperation with the ball rolling groove and has a non-loaded ball rolling passage arranged parallel to the loaded ball rolling groove, return members which are attached to both end surfaces of the movable block body in a relative movement direction and in which inner peripheral-side direction change grooves connecting a part of the loaded ball rolling passage and a part of the non-loaded ball rolling passage are formed, and a pair of end plates which is mounted on both end surfaces of the movable block body in the relative movement direction so as to cover the return members and in which outer peripheral-side direction change grooves are formed in surface sides where the end plates are mounted on the movable block body.
The balls rolling in the plurality of ball rolling grooves formed in the track rail are scooped up from the ball rolling groove by scooping portions in the lower edges of the end plate and enter a direction change passage formed by the inner peripheral-side direction change groove and the outer peripheral-side direction change groove. The ball passing through one direction change passage and circulating the non-loaded ball rolling passage is pushed by the following ball and enters the other direction change passage, and then enters the loaded ball rolling passage (between the ball rolling groove of the track rail and the loaded ball rolling groove of the movable block) again.
In the case of such a linear guide, there is a possibility that the scooping portion in the lower edge of the end plate is broken when the movable block is moved at high speed (equal to or faster than 2.5 m/s, for example). The motion guide device disclosed in Patent Literature 1 has been known as a motion guide device in which such a possibility is reduced and it is difficult for the scooping portion to be broken even when the movable block is moved at high speed.